Many portable devices, for example mobile telephones, are equipped with a display such as a glass or plastic display window for providing information to the user. Furthermore such display windows are now commonly used as touch sensitive inputs. The use of a touch sensitive input with the display has the advantage over a mechanical keypad in that the display may be configured to show a range of different inputs depending on the operating mode of the device. For example, in a first mode of operation the display may be enabled to enter a phone number by displaying a simple numeric keypad arrangement and in a second mode the display may be enabled for text input by displaying an alphanumeric display configuration such as a simulated Qwerty keyboard display arrangement.
Hearing Aid Compatibility (HAC) is to a certain level a mandatory feature at least in devices sold in North America. HAC enabled devices feature a coil located in the device configured to enable magnetic induction to transmit an audio signal to a hearing aid device in the user's ear. Typically the coil of an earpiece is used also as a HAC coil or the HAC coil is a discrete and separate coil.